Improvement in rotary steam-engines



QT sa up., i @tinted @anni ffii. i

ALFRED DUVALL, OF BALTIMRE, MARYLAND.

Letters PatentvNo. 83,941, dated November 10, 1868;

To all whom it mez/y conce/rn Be it known that I, ALFRED DUVALL, ofBaltimore, in thecounty of Baltimore, and State of Maryland, haveinvented a new and useful Improvement in Rotary- Pressure'Engines, to beoperated by steam or any other fluid or liquid; and I do hereby declarethat the following is a full, clear, and exact description oftheconstruction and operation thereof', reference being had to theaccompanying drawings, and letters of reference thereon, making a partof this specication, in which- Figure 1, plate 1, is a verticalcross-section.

Figure 2, plate 1, a longitudinal section ofthe springs, bar, andset-screws in the ends of the ellipse.

Figure 3, plate l, a cross-section ofthe same. Figure 4, plate 1, across-section of spring pressing against packing-rings.

Figure 5, plate l, a plan of same. Figure 6, plate 2, alongitudinalsection in elevation.

'l Figure 7 plate 3, a vertical cross-section, showing the engine withtwo valves.'

` To enable others skilled in mechanics to make and my invention, I willproceed to describe the constructionand operation o'f the same.

The character of my invention, as shown by the accompanying drawings,consists, first, in an elliptic piston, revolving within a cylinder of atrue circle, equal in diameter to the length of the ellipse, with one ortwo, as desired, oscillating and nearly-balanced valves; also, thearrangement ofthe end Vpackin g-rings, and appliances for adjusting thesame, and of weakening the 'points of the elliptic piston, by which theyare made elastic, and arrangement for adjusting the same, so as tqcompensate for wear; and also providing an oil or water-chamber in theends of the same, and the combinationaas shown by the accompanyingdrawings, as will be more fully described in this specification.

Fig. 1, plate 1, shows an engine with but one valve, and receiving theagent of power at but one point.

Fig. 7, plate 3, shows an engine of a more efcient character, having twovalves, and receiving the agent of-power at opposite points. When usingtwo valves, the longer points of the valves, pressing on the face of theellipse, are s'o prpportioned as to close the inletports at the time theexhaustA commences through the discharge-ports.

A is the shaft on which the revolving elliptic piston B is fastened. o

This piston is of an elliptical form, and has formed within the materialcomposing its outer walls, and at the points of its greatest diameter,chambersD D, which serve as oil-chambers, and at the same time theyserve to weaken the pistou at the points of its contact with thecylinder, so that by means ofthe set-screws H, bars Gr, and l springs F,the weakened or elastic portions may be set'out and brought into contactwith the .interior surface of said cylinder. v

O is the stationary cylinder in which the elliptic pis- 'to'nrevolves uD D are oil-chambers in the endsof the elliptic piston.

.E E are oil-holes Afor charging the oil-chambers D.

J, gum packing between the packing-rings I and K.

L are conicalsprings, pressing against the packingrings K, as shown infigs. 4 and 5, plate 1, and fig. 6, plate 2.

M are set-screws, 'pressing against the springs L.

N are flange-rings, bolted to the flanges of the cylinder C, and throughwhich the set-screws M work.

O are the stationary shafts, on which the valves P oscillate.

Q are the valve-chambers.

R R, recesses in the backs of the valves P, to be' iilled with Babbitmetal.

S, recess in valve l), forming an oil-chamber.

T, oil-tube, supplying oil-chamber S.

U, inlet-pipe and port.

V, exhaust-pipe and port. g

W, journal-stands, supporting engine-shaft.

X, bed-plate.

Y Y, lily-wheels. I

For reversing, I use two engines of' the same class, on the same shaft,or connected by couplings, with the necessary stop-valves, Sto., so asto operate either engine alternately', thereby giving a reverse motion.

Opf/ration.

The steam or other agent of power, ,being let on through a' valve in theinlet-pipe, presses against the front of rthe valve P, which forms anabutment, and the front, or part of theY valve bearing on the ellipticpiston,

is made a little longer than the back arm, by which means the valve isconstantly kept tight to the face of the elliptic piston during itsrevolutions. The point of the ellipse being moved a little beyond theinlet-port, the agent of power' acts on the same, and'causes it torevolve in the direction indicated by the arrows, and, from the momentumofthe iiy-wheels, a continuous rotary motion is maintained, and thepower transmitted from the shaft of the engine as may be desired.

What I claim as my invention, and desire to 'secure by Letters Patent,is- 1. An elliptical piston, constructed with elastic or yieldingsurfaces upon its points of greatest diameter, substantlallyas shown anddescribed.

2. The chambers D D, formed Within the piston, substantially as shownand described.

3. rlhe combination of the elliptical pistou B, the chambers D D, andthe set-screw H, bars G, and springs F, substantially as shown anddescribed.

4. The arrangement of the packing-rings K and I, rubber or elasticpacking J, spring L, and set-screw' M, substantially as shown anddescribed.

ALFRED DUVALL.

Witnesses:

SAMUEL Kann, A. LESLIE DUVALL.

